<?php


/*
 * 微信退款
 */
namespace WeixinPay;

class WeixinRefund
{
    protected $appid;
    protected $mch_id;
    protected $key;
    protected $out_trade_no;
    protected $total_fee;
    protected $refund_fee;
    protected $out_refund_no;
    protected $SSLCERT_PATH = 'apiclient_cert.pem';
    protected $SSLKEY_PATH = 'apiclient_key.pem';

    function __construct($appid, $mch_id, $key, $out_trade_no, $total_fee, $out_refund_no, $refund_fee)
    {
        $this->appid = $appid;
        $this->mch_id = $mch_id;
        $this->key = $key;
        $this->out_trade_no = $out_trade_no;
        $this->total_fee = $total_fee;
        $this->refund_fee = $refund_fee;
        $this->out_refund_no = $out_refund_no;
    }
    //向外暴露的微信退款接口
    public function refund()
    {
        $result = $this->weChatrefund();
        return $result;
        /*
        * <xml>
              <return_code><![CDATA[SUCCESS]]></return_code>
              <return_msg><![CDATA[OK]]></return_msg>
              <appid><![CDATA[wx2421b1c4370ec43b]]></appid>
              <mch_id><![CDATA[10000100]]></mch_id>
              <nonce_str><![CDATA[NfsMFbUFpdbEhPXP]]></nonce_str>
              <sign><![CDATA[B7274EB9F8925EB93100DD2085FA56C0]]></sign>
              <result_code><![CDATA[SUCCESS]]></result_code>
              <transaction_id><![CDATA[1008450740201411110005820873]]></transaction_id>
              <out_trade_no><![CDATA[1415757673]]></out_trade_no>
              <out_refund_no><![CDATA[1415701182]]></out_refund_no>
              <refund_id><![CDATA[2008450740201411110000174436]]></refund_id>
              <refund_channel><![CDATA[]]></refund_channel>
              <refund_fee>1</refund_fee>
           </xml>
           */
        if($result['return_code'] =='SUCCESS'){
            //退款申请成功
        }
    }

    private function weChatrefund()
    {
        $param = array(
            'appid'=> $this->appid,
            'mch_id'=> $this->mch_id,
            'nonce_str'=> $this->createNoncestr(),
            'out_refund_no'=> $this->out_refund_no,
            'out_trade_no'=> $this->out_trade_no,//微信订单号
            'total_fee'=> $this->total_fee,
            'refund_fee'=> $this->refund_fee,
        );
        $param['sign'] = $this->getSign($param);
        $xmldata = $this->arrayToXml($param);
        $xmlresult = $this->postXmlSSLCurl($xmldata,'https://api.mch.weixin.qq.com/secapi/pay/refund');
        $result = $this->xmlToArray($xmlresult);
        return $result;
    }

    /*
     * 对要发送到微信统一下单接口的数据进行签名
     */
    protected function getSign($Obj){
        foreach ($Obj as $k => $v){
            $Parameters[$k] = $v;
        }
        //签名步骤一：按字典序排序参数
        ksort($Parameters);
        $String = $this->formatBizQueryParaMap($Parameters, false);
        //签名步骤二：在string后加入KEY
        $String = $String."&key=".$this->key;
        //签名步骤三：MD5加密
        $String = md5($String);
        //签名步骤四：所有字符转为大写
        $result_ = strtoupper($String);
        return $result_;
    }

    /*
     *排序并格式化参数方法，签名时需要使用
     */
    protected function formatBizQueryParaMap($paraMap, $urlencode)
    {
        $buff = "";
        ksort($paraMap);
        foreach ($paraMap as $k => $v)
        {
            if($urlencode)
            {
                $v = urlencode($v);
            }
            //$buff .= strtolower($k) . "=" . $v . "&";
            $buff .= $k . "=" . $v . "&";
        }
        $reqPar = "";
        if (strlen($buff) > 0)
        {
            $reqPar = substr($buff, 0, strlen($buff)-1);
        }
        return $reqPar;
    }

    /*
     * 生成随机字符串方法
     */
    protected function createNoncestr($length = 32 ){
        $chars = "abcdefghijklmnopqrstuvwxyz0123456789";
        $str ="";
        for ( $i = 0; $i < $length; $i++ ) {
            $str.= substr($chars, mt_rand(0, strlen($chars)-1), 1);
        }
        return $str;
    }
//数组转字符串方法
    protected function arrayToXml($arr){
        $xml = "<xml>";
        foreach ($arr as $key=>$val)
        {
            if (is_numeric($val)){
                $xml.="<".$key.">".$val."</".$key.">";
            }else{
                $xml.="<".$key."><![CDATA[".$val."]]></".$key.">";
            }
        }
        $xml.="</xml>";
        return $xml;
    }

    protected static function xmlToArray($xml){
        $array_data = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
        return $array_data;
    }

//需要使用证书的请求
    private function postXmlSSLCurl($xml,$url,$second=30)
    {
        $ch = curl_init();
        //超时时间
        curl_setopt($ch,CURLOPT_TIMEOUT,$second);
        //这里设置代理，如果有的话
        //curl_setopt($ch,CURLOPT_PROXY, '8.8.8.8');
        //curl_setopt($ch,CURLOPT_PROXYPORT, 8080);
        curl_setopt($ch,CURLOPT_URL, $url);
        curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,FALSE);
        curl_setopt($ch,CURLOPT_SSL_VERIFYHOST,FALSE);
        //设置header
        curl_setopt($ch,CURLOPT_HEADER,FALSE);
        //要求结果为字符串且输出到屏幕上
        curl_setopt($ch,CURLOPT_RETURNTRANSFER,TRUE);
        //设置证书
        //使用证书：cert 与 key 分别属于两个.pem文件
        //默认格式为PEM，可以注释
//        curl_setopt($ch,CURLOPT_SSLCERTTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLCERT, '../'.$this->SSLCERT_PATH);
        //默认格式为PEM，可以注释
//        curl_setopt($ch,CURLOPT_SSLKEYTYPE,'PEM');
        curl_setopt($ch,CURLOPT_SSLKEY,'../'. $this->SSLKEY_PATH);
        //post提交方式
        curl_setopt($ch,CURLOPT_POST, true);
        curl_setopt($ch,CURLOPT_POSTFIELDS,$xml);
        $data = curl_exec($ch);
        //返回结果
        if($data){
            curl_close($ch);
            return $data;
        }
        else {
            $error = curl_errno($ch);
            echo "curl出错，错误码:$error"."<br>";
            curl_close($ch);
            return false;
        }
    }
}